The first "set" I bought for my kid back in 1996, a pair of O-27 Reading Alco FA units (6-18934) and a set of similarly-schemed O-27 passenger cars:
He was seven at the time and a huge fan of Batman/Power Rangers, so I figured this set was as close to a Dark Knight/Black Ranger set as we might find. Interestingly, I don't think the Reading ever ran an all-black scheme for passenger equipment (could be wrong). Cab units definitely had a black paint scheme, but I'm thinking the black passenger equipment was a bit of a fantasy scheme by Lionel.
On the layout, we ran this as
King Coal, the Reading train that ran between Philadelphia and Shamokin, Pennsylvania. We typically ran it with a baggage car, a combo, a couple of coaches, and an observation. We have a VistaDome as offered by Lionel, but rarely used it. VistaDome equipment on such a relatively short-haul eastern train seemed highly unlikely.
Anyway, the "set" hadn't seen track-time in probably fifteen years (at least), so we got it on the track recently and let it run. Quiet and smooth, it's a terrific conventional runner (even if those pilots are a bit ghastly).